Coordinates: 47°29′27″N 3°54′33″E / 47.4908°N 3.9092°E / 47.4908; 3.9092

Avallon is a commune in the Yonne department in Burgundy in center-eastern France.

Avallon is located 50 km south-southeast of Auxerre, served by a branch of the Paris-Lyon railway and by exit 22 of the A6 motorway. The old town, with many winding cobblestone streets flanked by traditional stone and woodwork buildings, is situated on a flat promontory, the base of which is washed on the south by the Cousin, on the east and west by small streams.

Chance finds the coins and pottery fragments and a fine head of Minerva are reminders of the Roman settlement carrying the Celtic name Aballo, a mutatio or post where fresh horses could be obtained. Two pink marble columns in the church of St-Martin du Bourg have been reused from an unknown temple (Princeton Encyclopedia). The Roman citadel, on a rocky spur overlooking the Cousin valley, has been Christianized as Montmartre ("Mount of the Martyrs").

In the year 470, the Romano-British king, Riothamus, disappeared (and presumably died) in the neighborhood of Avallon after being defeated by the Goths, against whom the Western Roman Emperor Anthemius had hired him to fight. This, and other aspects of his reign, has made him a candidate for the historical King Arthur, with Avallon becoming Arthurian Avalon. Avallon (Aballo) was in the Middle Ages the seat of a viscounty dependent on the duchy of Burgundy; on the death of Charles the Bold in 1477, it passed under the royal authority. The castle, mentioned as early as the seventh century,^{[citation needed]} has utterly disappeared.